binman: Allow updating entries that change size

So far we don't allow entries to change size when repacking. But this is
not very useful since it is common for entries to change size after an
updated binary is built, etc.

Add support for this, respecting the original offset/size/alignment
constraints of the image layout. For this to work the original image
must have been created with the 'allow-repack' property.

This does not support entry types with sub-entries such as files and
CBFS, but it does support sections.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/binman/control.py

@@ -118,11 +118,11 @@ def ReadEntry(image_fname, entry_path, decomp=True):
     return entry.ReadData(decomp)
 
 
-def WriteEntry(image_fname, entry_path, data, decomp=True):
+def WriteEntry(image_fname, entry_path, data, decomp=True, allow_resize=True):
     """Replace an entry in an image
 
     This replaces the data in a particular entry in an image. This size of the
-    new data must match the size of the old data
+    new data must match the size of the old data unless allow_resize is True.
 
     Args:
         image_fname: Image filename to process
@@ -130,18 +130,33 @@ def WriteEntry(image_fname, entry_path, data, decomp=True):
         data: Data to replace with
         decomp: True to compress the data if needed, False if data is
             already compressed so should be used as is
+        allow_resize: True to allow entries to change size (this does a re-pack
+            of the entries), False to raise an exception
+
+    Returns:
+        Image object that was updated
     """
     tout.Info("WriteEntry '%s', file '%s'" % (entry_path, image_fname))
     image = Image.FromFile(image_fname)
     entry = image.FindEntryPath(entry_path)
     state.PrepareFromLoadedData(image)
     image.LoadData()
+
+    # If repacking, drop the old offset/size values except for the original
+    # ones, so we are only left with the constraints.
+    if allow_resize:
+        image.ResetForPack()
     tout.Info('Writing data to %s' % entry.GetPath())
     if not entry.WriteData(data, decomp):
-        entry.Raise('Entry data size does not match, but resize is disabled')
+        if not image.allow_repack:
+            entry.Raise('Entry data size does not match, but allow-repack is not present for this image')
+        if not allow_resize:
+            entry.Raise('Entry data size does not match, but resize is disabled')
     tout.Info('Processing image')
-    ProcessImage(image, update_fdt=True, write_map=False, get_contents=False)
+    ProcessImage(image, update_fdt=True, write_map=False, get_contents=False,
+                 allow_resize=allow_resize)
     tout.Info('WriteEntry done')
+    return image
 
 
 def ExtractEntries(image_fname, output_fname, outdir, entry_paths,
@@ -264,7 +279,8 @@ def PrepareImagesAndDtbs(dtb_fname, select_images, update_fdt):
     return images
 
 
-def ProcessImage(image, update_fdt, write_map, get_contents=True):
+def ProcessImage(image, update_fdt, write_map, get_contents=True,
+                 allow_resize=True):
     """Perform all steps for this image, including checking and # writing it.
 
     This means that errors found with a later image will be reported after
@@ -277,6 +293,8 @@ def ProcessImage(image, update_fdt, write_map, get_contents=True):
         write_map: True to write a map file
         get_contents: True to get the image contents from files, etc., False if
             the contents is already present
+        allow_resize: True to allow entries to change size (this does a re-pack
+            of the entries), False to raise an exception
     """
     if get_contents:
         image.GetEntryContents()
@@ -309,6 +327,7 @@ def ProcessImage(image, update_fdt, write_map, get_contents=True):
             image.SetCalculatedProperties()
             for dtb_item in state.GetAllFdts():
                 dtb_item.Sync()
+                dtb_item.Flush()
         sizes_ok = image.ProcessEntryContents()
         if sizes_ok:
             break